A de Laval nozzle accelerates high-pressure subsonic gas to supersonic velocities through a converging-diverging cross-sectional geometry. In the converging section, the decreasing area accelerates the subsonic fluid until it reaches choked flow conditions (Mach 1) at the throat. In the diverging section, the expanding cross-section causes supersonic flow to expand isentropically, continuously converting thermal enthalpy into directed kinetic energy with declining static pressure and temperature.